gastric juice, digestive secretions of the gastric glands in the stomach, consisting chiefly of pepsin, hydrochloric acid, rennin, and mucin. The pH is strongly acid (0.9 to 1.5). Achlorhydria (a deficiency of hydrochloric acid in gastric juice) is present in pernicious anemia and stomach cancer. Excessive secretion of gastric juice may lead to mucosal irritation and peptic ulcer. See also achlorhydria, gastric analysis, peptic ulcer.